Effect of early intervention of dexamethasone for acute lung injury following open chest trauma and sea water immersion in dogs and the mechanism

Objective To investigate the effect of dexamethasone for acute lung injury( ALI) following open chest trauma and sea water immersion in dogs and its mechanism. Methods Sixteen healthy adult dogs were used to make the ALI models by seawater immersed thoracic cavity after open chest trauma. Then the ALI models were randomly assigned into the control group( CG) and the dexamethasone treatment group( DG),8 in each group. Dogs in the DG group were intravenously injected with 1 mg /kg dexamethasone( DG) 30 min after open chest trauma and sea water immersion,and dogs in the CG group were treated with equal normal saline. Arterial blood gas indexes( PaO2and PaO2/FiO2) and expression changes of alveolar surfactant protein-A( SP-A) and alveolar surfactant protein-B( SP-B) in the lung bronchoalveolar lavage fluid( BALF) and serum as well as the EVL-WI and ELI were observed. Results At 4 h after treatment,the PaO2and PaO2/FiO2in the DG group was significantly higher than that of the control group( P 0. 05),the EVL-WI and ELI in the DG group was lower than that of the control group( P 0. 05),and the SP-A and SP-B in the DG group in the BALF was higher than that of the CG group but lower than in the blood serum. Conclusion Dexamethasone can relieve hypoxia and pulmonary edema after open chest trauma and sea water immersion in dogs and its mechanism may be associated with the increase of the SP-A and SP-B contents in lungs.